Methods of making magnesium/transition metal alkoxide complexes and polymerization catalysts made therefrom

ABSTRACT

A method of halogenating a precursor to form a polymerization procatalyst is disclosed whereby a magnesium/transition metal-containing alkoxide complex precursor is contacted with a halogenating agent selected from alkylaluminum halide, TiX 4 , SiX 4 , BX 3 , and Br 2 , where halide and X are reach respectively a halogen, and when an alkylaluminum halide, TiX 4 , SiX 4 , BX 3 , and Br 2  are used as the halogenating agent, they are used together or in combination in a multi-step halogenation. The procatalyst then can be converted to an olefin polymerization catalyst by contacting it with a cocatalyst and optionally a selectivity control agent, and used to polymerize olefins in high yield with desired properties.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to methods of making olefinpolymerization catalysts from magnesium, transition metal andhalogen-containing olefin polymerization procatalysts, and their use asa catalyst component for the polymerization of olefin monomers. Theprocatalysts are prepared by halogenating a magnesium and transitionmetal-containing alkoxide complex, and optionally contacting thehalogenated product with an electron donor. The procatalyst then can beconverted to an olefin polymerization catalyst by contacting it with acocatalyst and optionally a selectivity control agent.

[0003] 2. Description of Related Art

[0004] Polymers and copolymers of lower α-olefins, particularly,ethylene, propylene and butylene are widely used throughout the world.These polymeric products are relatively inexpensive to manufacture, andthey exhibit a number of commercially useful properties. These polymersare most commonly utilized in the form of highly crystalline solids.During the polymerization process, whether it be by liquid pool, gasphase, slurry phase or any other commonly utilized process, it isbeneficial for the polymer particles (and consequently the catalystparticles) to be of a satisfactory shape and size. As examples: denserparticles allow for higher hourly production rates; spheroidal particlesallow for higher polymer bulk density; narrow particle size distributionallows for better gas phase fluidization. Overly small catalyst andpolymer particles (commonly called fines) are also undesirable.

[0005] When ethylene is polymerized, the process is less complicatedthan with higher olefins in that the product type is not greatlyinfluenced by the manner in which the ethylene molecules add to thegrowing polymeric chain during polymerization. The polymeric product ofethylene does not generally exist in stereoisomeric forms. The simplercatalysts required to effect this polymerization can normally beobtained by straightforward chlorination of a catalyst precursor. If theshape of the catalyst particle and thus the shape of the resultingpolymer particle is of importance, the catalyst precursor must besufficiently robust so that it can withstand the rigors of thischlorination step.

[0006] When propylene is polymerized, however, the presence of pendantmethyl groups on the polymeric chain provides a possibility of severalproduct types, depending on the steric regularity with which propylenemolecules add to the growing chain. Much if not most of the commercialpolypropylene results from the stereoregular addition of propylenemolecules in a regular head-to-tail manner. The form of polymer having asubstantial proportion of random addition of propylene units is termedatactic and this amorphous form is less desirable. If present in asignificant proportion, the atactic polymer must be removed through anextraction process to provide a more desirable crystalline material.

[0007] These polymers typically are formed by using a polymerizationcatalyst. The activity of the catalyst is significant in that the morepolymer produced per unit weight of catalyst the better. The earlytitanium, chromium or vanadium catalysts were of low activity and theproduct contained a significant proportion of catalyst residues. Theseresidues had to be removed in an effort to obtain commerciallysatisfactory properties.

[0008] More recent titanium-based olefin polymerization catalysts arestereoregulating and have sufficient activity to avoid extraction anddeashing. These high activity catalysts typically are prepared viachlorination of a magnesium containing precursor, in the presence of anelectron donor compound, to form a solid procatalyst that usuallycontains magnesium, titanium and halide moieties, and comprisesadditionally a cocatalyst (usually an organoaluminum compound) and anoptional selectivity control agent (SCA) for propylene polymerization.The magnesium containing complex is typically referred to as a“precursor”, the solid titanium-containing compound typically isreferred to as a “procatalyst”, the organoaluminum compound, whethercomplexed or not, usually is referred to as the “cocatalyst” and thethird component external electron donor, whether used separately orpartially or totally complexed with the organoaluminum compound, isreferred to as the “selectivity control agent.” Throughout thisdisclosure, these terms will be used in accordance with theaforementioned designations. As before, if the shape of the catalystparticle and thus the shape of the resulting polymer particle is ofimportance, the catalyst precursor must be sufficiently robust so thatit can withstand the rigors of the chlorination process.

[0009] Many chemical combinations of procatalysts, cocatalysts andselectivity control agents are known in the art to produce activecatalysts. Through considerable experience, however, certain materialsare of greater interest than others. For example, there is significantresearch in the area of procatalysts, which typically contain somechemical combination of magnesium, titanium tetrachloride and aninternal electron donor. These internal electron donors usually areoxygen containing compounds such as tetrahydrofuran and aromatic esterssuch as ethyl benzoate or ethyl p-toluate. Conventional cocatalystsinclude an aluminum trialkyl such as triethylaluminum ortriisobutylaluminum that is often complexed with a portion of theselectivity control agent (or external electron donor), which also istypically an aromatic ester or an organosilane. Although variations inany of these catalyst components will influence the performance of theresultant catalyst, the component that appears to offer the greatestopportunity for modification to produce greater catalyst activity is theprocatalyst.

[0010] The literature is rife with disclosures relating to the variousknown methods of preparing procatalysts. For example, Kioka, et al.,U.S. Pat. No. 4,330,649, the disclosure of which is incorporated byreference herein in its entirety, describes a solid catalyst component(procatalyst) that is prepared by heating a soluble magnesium compoundsuch as magnesium chloride with a higher alcohol in the presence of anester to produce a solution. This solution contains a “precursor” of theprocatalyst, which then is added to titanium tetrachloride and anelectron donor (internal) to form the procatalyst. A number of UnitedStates patents issued to Robert C. Job (and Robert C. Job, et al.,)describe various mechanisms for preparing magnesium-containing,titanium-containing compounds that are useful as precursors for theproduction of procatalysts that are ultimately useful in preparingcatalysts for the polymerization of α-olefins. For example, U.S. Pat.Nos. 5,034,361; 5,082,907; 5,151,399; 5,229,342; 5,106,806; 5,146,028;5,066,737; 5,122,494, 5,124,298, and 5,077,357, the disclosures of whichare incorporated by reference herein in their entirety, disclose variousprocatalyst precursors. U.S. Pat. No. 5,034,361 discloses solubilizing amagnesium alkoxide in an alkanol solvent by interaction of the magnesiumalkoxide compound and certain acidic materials. This magnesium alkoxidethen can be used either directly as a magnesium-containing catalystprecursor, or can be reacted with various titanium compounds to producea magnesium and titanium-containing catalysts precursor.

[0011] U.S. Pat. Nos. 5,082,907; 5,151,399; 5,229,342; 5,106,806;5,146,028; 5,066,737; 5,122,494, 5,124,298, and 5,077,357 disclosevarious magnesium and titanium-containing catalyst precursors, some ofwhich are prepared by using the aforementioned magnesium alkoxide as astarting material. These precursors are not active polymerizationcatalysts, and they do not contain any effective amounts of electrondonor. Rather, the precursors are used as starting materials in asubsequent conversion to an active procatalyst. Magnesium andtitanium-containing procatalysts are formed by chlorinating themagnesium and titanium-containing precursor with a tetravalent titaniumhalide, an optional hydrocarbon and an optional electron donor. Theresulting procatalyst solid then is separated from the reaction slurry(by filtration, precipitation, crystallization, and the like). Theseprocatalysts then are converted to polymerization catalysts by reactionwith, for example, an organoaluminum compound and a selectivity controlagent. U.S. Pat. Nos. 5,122,494 and 5,371,157, the disclosures of whichare incorporated herein by reference in their entirety, disclosetreating those various magnesium and titanium-containing catalystprecursors with ethylaluminum dichloride (EADC) or diethylaluminumchloride (DEAC), as chlorinating agents, to obtain procatalysts via aone-step chlorination. Those procatalysts are then converted topolymerization catalysts by reaction with, for example, anorganoaluminum compound and a selectivity control agent.

[0012] These known polymerization catalysts typically are prepared bycontacting the solid reaction product, consisting essentially ofmagnesium alkoxide, titanium alkoxide and phenoxide (approximatelyMg₃Ti(OR)₈X₂ where X=OAr), with an alkylaluminum halide. While such aprecursor is relatively simple to prepare, and useful for thepolymerization of ethylene, they typically are produced in the form ofpowders which are not satisfactory for a gas phase process and even inslurry process produce deleteriously high fines levels. U.S. Pat. No.5,124,298 teaches the preparation of a similar magnesium/titaniumalkoxide precursor which differs from the one above in having X beprimarily halide (instead of phenoxide) and being obtained via ametathesis precipitation reaction process as a controlled morphology(nearly spheroidal) granular material.

[0013] Many of the conventional halogenation methods are too rigorous tothe extent that they adversely affect the morphology of the solidprecursor material thereby resulting in poor morphology catalysts, andultimately, poor polymer product. In addition, the procatalysts usuallyare not specifically tailored to control the catalyst decay rate,control the molecular weight distribution of the polymer, or to producepolymer having dissymetric molecular weight distributions. Moreover,many of the methods described in the prior art relate to magnesium andtitanium containing complexes, and do not provide the flexibility ofmaking procatalysts from transition metals other than titanium. Finally,the conventional Ziegler-type procatalysts described above all arecontacted with relatively inexpensive cocatalysts, such astriethylaluminum, and have not heretofore been used with cocatalystslike aluminoxanes, which typically are employed with metallocenecatalysts, to form a polyolefin polymerization catalyst.

SUMMARY OF THE INVENTION

[0014] Thus, there exists a need to develop a method of making aprocatalyst that does not adversely affect the morphology of theprecursor. There also exists a need to develop a method of making aprocatalyst that can be converted to an olefin polymerization catalystcapable of producing polymers in high yield, low fines, improved averageparticle size and increased bulk density. There also exists a need toprovide a method of making a substantially spheroidal procatalyst havingcontrolled catalyst decay rates, and a method of making a substantiallyspheroidal procatalyst capable of making tailored polymer particleshaving desired molecular weight distributions (narrow, broad,dissimilar, etc.). In addition, there exists a need to develop a methodof halogenating a magnesium/transition metal-containing precursorcomplex that has the flexibility and applicability to a variety oftransition metals, and which can be used with a variety of cocatalyststo polymerize olefins. A need also exists to develop a procatalyst andmethod of making a procatalyst that does not suffer from any of theaforementioned disadvantages.

[0015] In accordance with these and other features of the invention,there is provided a method of making a procatalyst including contactinga magnesium/transition metal-containing alkoxide complex with at leastone halogenating agent selected from alkylaluminum halide, TiX₄, SiX₄,BX₃, and Br₂, where halide and X are each respectively a halogen,preferably chlorine or bromine, and if an alkylaluminum halide, TiX₄,SiX₄, and/or Br₂ are used as the at least one halogenating agent, theyare used together with another halogenating agent or in combination withanother halogenating agent in a multi-step halogenation.

[0016] In accordance with an additional feature of the presentinvention, there is provided a procatalyst prepared by halogenating theabove-mentioned precursor with the above-mentioned halogenating agent,and optional electron donor, where the procatalyst, when converted to acatalyst and used to polymerize at least one olefin, has controlledcatalytic decay and can yield polymer having tailored molecular weightdistributions.

[0017] The invention also provides a high activity olefin polymerizationprocatalyst that is prepared by the above-mentioned process and whichoptionally contains an electron donor and a hydrocarbon. The inventionadditionally provides a high activity olefin polymerization catalystthat comprises: (i) the above-described procatalyst; (ii) anorganoaluminum cocatalyst; and optionally, (iii) a selectivity controlagent. The invention also provides methods of making each of theabove-described procatalysts and catalysts. In addition, the inventionprovides methods of polymerizing olefins (homopolymers, copolymers,terpolymers, etc.) by contacting an olefin monomer (or monomers) withthe above-described high activity olefin polymerization catalyst.

[0018] These and other features of the present invention will be readilyapparent to those skilled in the art upon reading the detaileddescription that follows.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0019] Throughout this description, the expression “if an alkylaluminumhalide, TiX₄, SiX₄, and Br₂ are used as the halogenating agent, they areused together with another halogenating agent or in combination withanother halogenating agent in a multi-step halogenation” denotes amethod whereby if any of the halogenating agents are used by themselvesin one step to halogenate a procatalyst precursor complex, anotherhalogenating agent (same or different) is used in a subsequent step tohalogenate a procatalyst precursor complex. This expression alsoencompasses a method whereby a mixture of one or more of thehalogenating agents can be used in one halogenation step, and anotheragent or mixture of agents (including the same mixture) can be used in asubsequent halogenation. The following are representative examples ofpossible halogenation treatments:

[0020] 1. Two consecutive EADC treatments;

[0021] 2. An EASC treatment followed by EADC;

[0022] 3. TiCl₄ treatment followed by EADC treatment;

[0023] 4. BCl₃ treatment;

[0024] 5. SiCl₄ followed by EADC;

[0025] 6. mixed TiCl₄/SiCl₄ treatment followed by EADC;

[0026] 7. SiCl₄ followed by mixed EADC/BCl₃; and

[0027] 8. Br₂ first step followed by EADC.

[0028] Other possible configurations within the context of the aboveexpression will be readily apparent to those skilled in the art uponreview of this disclosure.

[0029] In the present invention, it is preferred that if TiX₄ or SiX₄are used as a halogenating agent, they are used in a multi-stephalogenation where a different halogenating agent is used in one of thehalogenation steps. For example, if TiCl₄ or a mixture of TiCl₄ andSiCl₄ is used in one step, then a different halogenating agent is usedin another step of the multi-step halogenation (contact with TiCl₄followed by contact with SiCl₄, or vice versa, or contact with TiCl₄followed by contact with EADC, DEAC, and the like). As will beappreciated by those skilled in the art, multi-step halogenation denotesat least two halogenation steps, (preferably two), but more than twosteps could also be used.

[0030] Throughout this description the term “precursor” and theexpression “procatalyst precursor” denotes a solid material thatcontains magnesium and a transition metal, but does not contain anelectron donor, and which can be converted to a “procatalyst” (definedbelow) by contacting it with a halogenating agent such as alkylaluminumhalide or tetravalent titanium halide (preferably TiCl₄) and optionallyan electron donor. Throughout this description, the term “procatalyst”denotes a solid material that is an active catalyst component, and thatcan be converted to a polymerization catalyst by contact with anorganoaluminum compound (preferably triethyl aluminum (TEAL) andaluminoxane), and an optional external donor, or selectivity controlagent.

[0031] The present invention contemplates the formation of an olefinpolymerization catalyst by contacting at least one halogenating agentwith a complex magnesium-containing, transition metal-containingalkoxide compound precursor prepared by reaction of, for example,magnesium alkoxide, a transition metal-containing compound such astitanium tetraalkoxide and a phenolic compound or a halogen-containingcompound. Such complex precursor compounds are described, inter alia, inU.S. Pat. Nos. 5,122,494, 5,124,298, and 5,371,157. The complex alkoxideprecursors are of somewhat variable stoichiometry but have the generalillustrative formula

Mg₃Tr(OR)₈ X₂

[0032] wherein Tr is a transition metal selected from those transitionmetals having an oxidation state of at least +3, and preferably isselected from titanium, zirconium, hafnium, chromium, iron and vanadium,R independently is alkyl of up to 4 carbon atoms inclusive and Xindependently is a halogen or a monovalent anion derived from a phenoliccompound. The resulting catalyst, employed in the presence of or in theabsence of a selectivity control agent, is used to polymerize orcopolymerize lower α-olefins such as ethylene or propylene. Thepolyolefin product is produced at a relatively high catalystproductivity and has excellent properties. In addition, the halogenationof the precursor can be conducted to tailor a polyolefin product havinga desired molecular weight distribution (broad, narrow, dissimilar,etc.). Skilled artisans are capable of carrying out the halogenation totailor polyolefin products using the guidelines provided herein.

[0033] The complex magnesium-containing, transition metal-containingalkoxide compound can be produced by any of the methods described inU.S. Pat. Nos. 5,122,494, 5,124,298, and 5,371,157, including themodification of substituting the titanium tetraalkoxide with a suitabletransition metal containing compound. The complex magnesium-containing,transition metal-containing alkoxide compound preferably can be producedby reacting a magnesium alkoxide, a titanium or a zirconiumtetraalkoxide, an optional halide, preferably titanium tetrahalide, anda phenolic compound in the presence of an inert reaction diluent. Thediluent then can be removed to produce, as a particulate solid, thecomplex alkoxide compound. This solid then can be treated with ahalogenating agent to produce the olefin polymerization procatalyst ofthe invention. This procatalyst then can be used, in the optionalpresence of selectivity control agent, to promote the polymerization oflower α-olefins by polymerization techniques which are largelyconventional.

[0034] The alkoxide moieties of the magnesium alkoxide are the same asor are different from the alkoxide moieties of the titaniumtetraalkoxide or other transition metal containing alkoxides. Moreover,the alkoxide moieties of one metal alkoxide reactant are the same as orare different from the alkoxide moieties of the other metal alkoxidereactant. In part for reasons of complex alkoxide purity, it ispreferred that all alkoxide moieties of both metal alkoxides be thesame. The preferred alkoxide moieties are methoxide or ethoxide (R ismethyl or ethyl) and particularly preferred is ethoxide. Magnesiumethoxide, titanium tetraethoxide and zirconium tetraethoxide are thepreferred metal alkoxide reactants for the production of the complexmetal alkoxide compound.

[0035] The phenolic compound that can be used as a reactant in theproduction of the complex alkoxide compound preferably is selected fromphenol or an activated phenol. By the term “activated phenol” is meant amonohydroxylic phenol of one aromatic ring having aromatic ringsubstituents other than hydrogen which serve to alter the pKa of thephenolic compound. Such substituent groups are free from active hydrogenatoms and include halogen, e.g., chlorine or bromine, alkyl andparticularly alkyl of up to 4 carbon atoms inclusive, and dialkylaminowherein each alkyl has up to 4 carbon atoms inclusive. Suitablesubstituent groups do not include hydroxy but may include aldehyde.Illustrative of suitable phenolic compounds are phenol, p-cresol,o-cresol, 3-methoxyphenol, 2,6-di-t-butyl-4-methylphenol (BHT),2,4-diethylphenol, p-chlorophenol, p-bromophenol, 2,4-dichlorophenol,p-dimethylaminophenol, salicyl aldehyde and m-diethylaminophenol.

[0036] The contacting of the magnesium alkoxide, transition metalcompound, optional halide, and phenolic compound preferably takes placeat an elevated temperature in an inert reaction diluent. The reactiondiluent is one in which all reactants are at least partially soluble andwhich does not react with the reactants or the complex alkoxide product.Preferred reaction diluents are hydrocarbon such as isooctane,isopentane or n-heptane, or are halohydrocarbon such as methylenechloride, carbon tetrachloride or chlorobenzene. The contactingpreferably takes place at a reaction temperature from about 50° C. toabout 90° C. Contacting typically is effected in a suitable reactor andis facilitated by conventional procedures such as shaking, stirring orrefluxing. The phenolic compound preferably is provided in a quantity offrom about 0.1 mole to about 4 moles per mole of transition metalcontaining compound (e.g., titanium tetraalkoxide), but preferably in aquantity of from about 0.5 mole to about 2 moles per mole of transitionmetal. The magnesium alkoxide can be provided in a quantity from about1.5 mole to about 8 moles per mole of transition metal containingcompound (e.g., titanium tetraalkoxide). Preferred quantities ofmagnesium alkoxide are from about 3 moles to about 6 moles per mole oftransition metal containing compound.

[0037] The product of the contacting of the magnesium alkoxide, thetransition metal containing compound, optional halide, and phenoliccompound in the inert reaction diluent is a solution of the complexalkoxide compound in the diluent. To obtain the solid complex alkoxidecompound, the complex alkoxide compound is separated from the diluent byany suitable means described in any of the aforementioned patents. Thesolid product resulting from either modification is the complex alkoxidecompound useful as a catalyst component.

[0038] The conversion of the complex alkoxide compound to the olefinpolymerization catalyst is by treatment with at least one halogenatingagent selected from alkylaluminum halide, TiX₄, SiX₄, BX₃, and Br₂,where halide and X are each respectively a halogen, preferably chlorineor bromine. Suitable alkylaluminum halides have from 1 to 2 alkyl groupsindependently of up to 8 carbon atoms and from 2 to 1 halide moieties.The preferred alkylaluminum halides are represented by the formula

R_(n)AlY_(3-n)

[0039] wherein R has the previously stated meaning, (R independently isalkyl of up to 4 carbon atoms inclusive), Y is chlorine or bromine and nis 1 or 2. Illustrative of such alkylaluminum halides are ethylaluminumdichloride (EADC), ethylaluminum sesquichloride (EASC), diethylaluminumchloride (DEAC), diethylaluminum bromide, propylaluminum dibromide,dibutylaluminum chloride and methylaluminum dibromide. In general, thecompounds of the above formula wherein n is 2 are preferred as are thecompounds wherein R is ethyl. Particularly preferred as alkylaluminumhalide is EADC.

[0040] Other halogenating agents such as TiX₄, SiX₄, BX₃ and Br₂ can beused, where X is any halogen. Preferably, X is chlorine or bromine, andmost preferably, X is chlorine. Particularly preferred halogenatingagents are TiCl₄ and SiCl₄.

[0041] The reaction of the solid complex alkoxide precursor and thehalogenating agent preferably is conducted by contacting the reactantsin a multi-step halogenation process. When BCl₃ is used as thehalogenating agent, a single contact will suffice, although it ispreferred to use a multi-step halogenation process. By multi-stephalogenation process, it is intended to encompass contacting the solidcomplex alkoxide precursor more than once with at least one halogenatingagent. For example, the solid complex alkoxide precursor can becontacted once with a combination of TiX₄ and SiX₄, followed by furthercontact with additional halogenating agent which may be the same ordifferent from the first agent(s).

[0042] Insofar as many of the halogenating agents listed above areliquid, a preferred method of contacting is by mixing the halogenatingagent halide and the complex alkoxide precursor at an elevatedtemperature. Suitable contacting temperatures range anywhere from about20° C. to about 100° C., but preferably from about 35° C. to about 90°C. To insure adequate contacting, a diluent such as a hydrocarbon orhalohydrocarbon may be used but in other modifications, no diluent ispresent during the contacting. Subsequent to the contacting ofhalogenating agent and the complex alkoxide precursor, the resultingsolid typically is washed with light hydrocarbon, e.g., isooctane, toremove unreacted materials. This solid is useful as such as an olefinpolymerization catalyst.

[0043] The halogenating agent can be provided in any amount sufficientto halogenate the complex alkoxide precursor. Preferably, thehalogenating agent is provided in an amount of from about 1 mole toabout 150 moles per mole of transition metal of the complex alkoxideprecursor. Particularly preferred quantities of halogenating agent rangeanywhere from about 10 moles to about 30 moles per mole of transitionmetal.

[0044] Instead of, or in addition to using a phenolic compound toprepare the complex alkoxide precursor, any clipping agent species thatis capable of assisting in the breakup of a polymeric magnesiumalkoxide. Specifically, clipping agents include: (i) those specieswhich, in large excess are capable of dissolving magnesium alkoxides;(ii) large anions; and (iii) those that prevent magnesium alkoxides frompolymerizing. Preferably, the clipping agents are selected from HCHO,CO₂, B(OEt)₃, SO₂, Al(OEt)₃, CO₃ ^(═), Br⁻, (O₂COEt)⁻, Si(OR)₄,R′Si(OR)₃, and P(OR)₃. In the above compounds, R and R′ representhydrocarbon groups, preferably alkyl groups, containing from 1-10 carbonatoms, and preferably R and R′ are the same or different and are methylor ethyl. Other agents that release large anions or form large anions insitu (i.e., clipping agent precursors) can be used, such as MgBr₂,carbonized magnesium ethoxide (magnesium ethyl carbonate), calciumcarbonate, and the like.

[0045] Because the complex alkoxide precursor already contains activemetal species, it is not necessary that the halogenating agent be atransition metal halide, and if the halogenating agent is a transitionmetal halide, much less of it can be used. Preferably, the precursor iscontacted with a halogenating agent in an amount such that theequivalents of available halide are about 2 to 4 times the sum of 2times the magnesium equivalents+4 times the titanium equivalents,established by elemental analysis to be contained in the precursor.

[0046] The magnesium and transition metal-containing procatalyst servesas one component of a Ziegler-Natta catalyst system where it iscontacted with a cocatalyst and optionally, a selectivity control agent.The cocatalyst component employed in the Ziegler-Natta catalyst systemmay be chosen from any of the known activators of olefin polymerizationcatalyst systems employing a transition metal halide, but organoaluminumcompounds are preferred. Illustrative organoaluminum cocatalysts includetrialkylaluminum compounds, alkyaluminum alkoxide compoundsalkylaluminoxane compounds and alkylaluminum halide compounds in whicheach alkyl independently has from 2 to 6 carbon atoms inclusive. Thepreferred organoaluminum cocatalysts are halide free and particularlypreferred are the trialkylaluminum compounds. Such suitableorganoaluminum cocatalysts include compounds having the formulaAl(R′″)_(d)X_(e)H_(f) wherein: X is F, Cl, Br, I or OR″″, R′″and R″″ aresaturated hydrocarbon radicals containing from 1 to 14 carbon atoms,which radicals may be the same or different, and, if desired,substituted with any substituent which is inert under the reactionconditions employed during polymerization, d is 1 to 3, e is 0 to 2, fis 0 or 1, and d+e+f=3. Such cocatalysts can be employed individually orin combination thereof and include compounds such as Al(C₂H₅)₃,Al(C₂H₅)₂Cl, Al₂(C₂H₅)₃Cl₃, Al(C₂H₅)₂H, Al(C₂H₅)₂(OC₂H₅), Al(i-C₄H₉)₃,Al(i-C₄H₉)₂H, Al(C₆H₁₃)₃ and Al(C₈H₁₇)₃.

[0047] Preferred organoaluminum cocatalysts are triethyl aluminum,triisopropyl aluminum, triisobutyl aluminum and diethylhexyl aluminum.Triethyl aluminum is a preferred trialkyl aluminum cocatalyst.

[0048] The organoaluminum cocatalyst also can be an aluminoxane such asmethylaluminoxane (MAO) or modified methylaluminoxane (MMAO), or a boronalkyl. The method of preparing aluminoxanes is well known in the art.Aluminoxanes may be in the form of oligomeric linear alkyl aluminoxanesrepresented by the formula:

[0049] or oligomeric cyclic alkyl aluminoxanes of the formula:

[0050] wherein s is 1-40, preferably 10-20; p is 3-40, preferably 3-20;and R*** is an alkyl group containing 1 to 12 carbon atoms, preferablymethyl or an aryl radical such as a substituted or unsubstituted phenylor naphthyl radical. In the case of MAO, R*** is methyl, whereas inMMAO, R*** is a mixture of methyl and C2 to C12 alkyl groups whereinmethyl comprises about 20 to 80 percent by weight of the R*** group.

[0051] The organoaluminum cocatalyst, during formation of the olefinpolymerization catalyst, is preferably employed in a molar ratio ofaluminum to transition metal of the procatalyst of from about 1:1 toabout 150:1, but more preferably in a molar ratio of from about 10:1 toabout 100:1.

[0052] The final component of the Ziegler-Natta catalyst system is theoptional selectivity control agent (SCA), or external electron donor.Typical SCAs are those conventionally employed in conjunction withtitanium-based procatalysts and organoaluminum cocatalysts. Illustrativeof suitable selectivity control agents are those classes of electrondonors employed in procatalyst production as described above as well asorganosilane compounds including alkylakoxysilanes andarylalkoxysilanes. Particularly suitable silicon compounds of theinvention contain at least one silicon-oxygen-carbon linkage. Suitablesilicon compounds include those having the formula R¹ _(m)SiY_(n)X_(p)wherein: R¹ is a hydrocarbon radical containing from 4 to 20 carbonatoms, Y is —OR² or —OCOR² wherein R² is a hydrocarbon radicalcontaining from 1 to 20 carbon atoms, X is hydrogen or halogen, m is aninteger having a value of from 0 to 3, n is an integer having a value offrom 1 to 4, p is an integer having a value of from 0 to 1, andpreferably 0, and m+n+p=4. R¹ should be such that there is at least onenon-primary carbon in the alkyl and preferably, that such non-primarycarbon is attached directly to the silicon atom. Examples of R¹ includecyclopentyl, t-butyl, isopropyl or cyclohexyl. Examples of R² includeethyl, butyl, isopropyl, phenyl, benzyl and t-butyl. Examples of X areCl and H.

[0053] Each R¹ and R² may be the same or different, and, if desired,substituted with any substituent which is inert under the reactionconditions employed during polymerization. Preferably, R² contains from1 to 10 carbon atoms when it is aliphatic and may be sterically hinderedor cycloaliphatic, and from 6 to 10 carbon atoms when it is aromatic.Silicon compounds in which two or more silicon atoms are linked to eachother by an oxygen atom, i.e., siloxanes or polysiloxanes, may also beemployed, provided the requisite silicon-oxygen-carbon linkage is alsopresent. The preferred selectivity control agents are alkylalkoxysilanessuch as ethyldiethoxysilane, diisobutyl dimethoxysilane,cyclohexylmethyldimethoxysilane, propyl trimethoxysilane, dicyclohexyldimethoxysilane, and dicyclopentyl dimethoxysilane. In one modification,the selectivity control agent is a portion of the electron donor addedduring procatalyst production. In an alternate modification theselectivity control agent is provided at the time of the contacting ofprocatalyst and cocatalyst. In either modification, the selectivitycontrol agent is provided in a quantity of from 0.1 mole to about 100moles per mole of transition metsl in the procatalyst. Preferredquantities of selectivity control agent are from about 0.5 mole to about25 mole per mole of transition metal in the procatalyst.

[0054] The olefin polymerization catalyst can be produced by any knownprocedure of contacting the procatalyst, the cocatalyst and theselectivity control agent. The method of contacting is not critical. Inaddition, the catalyst components can be precontacted prior topolymerization to form a preactivated catalyst, or the components can becontacted with an olefin monomer to form a prepolymerized catalyst. Inone modification, the catalyst components simply are mixed in a suitablereactor and the preformed catalyst thereby produced is introduced intothe polymerization reactor when initiation of polymerization is desired.In an alternate modification, the catalyst components are introducedinto the polymerization reactor where the catalyst is formed in situ.

[0055] The olefin polymerization catalyst may be used in slurry, liquidphase, gas phase and liquid monomer-type reaction systems as are knownin the art for polymerizing olefins. Polymerization preferably isconducted in a fluidized bed polymerization reactor, however, bycontinuously contacting an alpha-olefin having 2 to 8 carbon atoms withthe components of the catalyst system, i.e, the solid procatalystcomponent, cocatalyst and optional SCAs. In accordance with the process,discrete portions of the catalyst components can be continually fed tothe reactor in catalytically effective amounts together with thealpha-olefin while the polymer product is continually removed during thecontinuous process. Fluidized bed reactors suitable for continuouslypolymerizing alpha-olefins have been previously described and are wellknown in the art. Fluidized bed reactors useful for this purpose aredescribed, e.g., in U.S. Pat. Nos. 4,302,565, 4,302,566 and 4,303,771,the disclosures of which are incorporated herein by reference. Thoseskilled in the art are capable of carrying out a fluidized bedpolymerization reaction using the guidelines provided herein.

[0056] It is preferred sometimes that such fluidized beds are operatedusing a recycle stream of unreacted monomer from the fluidized bedreactor. In this context, it is preferred to condense at least a portionof the recycle stream. Alternatively, condensation may be induced with aliquid solvent. This is known in the art as operating in “condensingmode.” Operating a fluidized bed reactor in condensing mode generally isknown in the art and described in, for example, U.S. Pat. Nos. 4,543,399and 4,588,790, the disclosures of which are incorporated by referenceherein in their entirety. The use of condensing mode has been found tolower the amount of xylene solubles in isotactic polypropylene andimprove catalyst performance when using the catalyst of the presentinvention.

[0057] The catalyst composition may be used for the polymerization ofolefins by any suspension, solution, slurry, or gas phase process, usingknown equipment and reaction conditions, and is not limited to anyspecific type of reaction system. Generally, olefin polymerizationtemperatures range from about 0° C. to about 200° C. at atmospheric,subatmospheric, or superatmospheric pressures. Slurry or solutionpolymerization processes may utilize subatmospheric or superatmosphericpressures and temperatures in the range of about 40° C. to about 110° C.A useful liquid phase polymerization reaction system is described inU.S. Pat. No. 3,324,095. Liquid phase reaction systems generallycomprise a reactor vessel to which olefin monomer and catalystcomposition are added, and which contains a liquid reaction medium fordissolving or suspending the polyolefin. The liquid reaction medium mayconsist of the bulk liquid monomer or an inert liquid hydrocarbon thatis nonreactive under the polymerization conditions employed. Althoughsuch an inert liquid hydrocarbon need not function as a solvent for thecatalyst composition or the polymer obtained by the process, it usuallyserves as solvent for the monomers employed in the polymerization. Amongthe inert liquid hydrocarbons suitable for this purpose are isopentane,hexane, cyclohexane, heptane, benzene, toluene, and the like. Reactivecontact between the olefin monomer and the catalyst composition shouldbe maintained by constant stirring or agitation. The reaction mediumcontaining the olefin polymer product and unreacted olefin monomer iswithdrawn from the reactor continuously. The olefin polymer product isseparated, and the unreacted olefin monomer and liquid reaction mediumare recycled into the reactor.

[0058] Preferably, gas phase polymerization is employed, withsuperatmospheric pressures in the range of 1 to 1000, preferably 50 to400 psi, most preferably 100 to 300 psi, and temperatures in the rangeof 30 to 130° C., preferably 65 to 110° C. Stirred or fluidized bed gasphase reaction systems are particularly useful. Generally, aconventional gas phase, fluidized bed process is conducted by passing astream containing one or more olefin monomers continuously through afluidized bed reactor under reaction conditions and in the presence ofcatalyst composition at a velocity sufficient to maintain a bed of solidparticles in a suspended condition. A stream containing unreactedmonomer is withdrawn from the reactor continuously, compressed, cooled,optionally fully or partially condensed as disclosed in U.S. Pat. Nos.4,528,790 and 5,462,999, and recycled to the reactor. Product iswithdrawn from the reactor and make-up monomer is added to the recyclestream. As desired for temperature control of the system, any gas inertto the catalyst composition and reactants may also be present in the gasstream. In addition, a fluidization aid such as carbon black, silica,clay, or talc may be used, as disclosed in U.S. Pat. No. 4,994,534.

[0059] Polymerization may be carried out in a single reactor or in twoor more reactors in series, and is conducted substantially in theabsence of catalyst poisons. Organometallic compounds may be employed asscavenging agents for poisons to increase the catalyst activity.Examples of scavenging agents are metal alkyls, preferably aluminumalkyls, most preferably triisobutylaluminum.

[0060] The precise procedures and conditions of the polymerization arebroadly conventional but the olefin polymerization process, by virtue ofthe use therein of the polymerization catalyst formed from the solidprecursor, provides polyolefin product having a relatively high bulkdensity in quantities that reflect the relatively high productivity ofthe olefin polymerization catalyst. In addition, the polymeric productsproduced in the present invention have a reduced level of fines.

[0061] Conventional additives may be included in the process, providedthey do not interfere with the operation of the catalyst composition informing the desired polyolefin.

[0062] When hydrogen is used as a chain transfer agent in the process,it is used in amounts varying between about 0.001 to about 10 moles ofhydrogen per mole of total monomer feed. Also, as desired fortemperature control of the system, any gas inert to the catalystcomposition and reactants can also be present in the gas stream.

[0063] The polymerization product of the present invention can be anyproduct, homopolymer, copolymer, terpolymer, and the like. Usually, thepolymerization product is a homopolymer such as polyethylene orpolypropylene, particularly polypropylene. Alternatively, the catalystand process of the invention are useful in the production of copolymersincluding copolymers of ethylene and propylene such asethylene-propylene rubber (EPR) and polypropylene impact copolymers whentwo or more olefin monomers are supplied to the polymerization process.Those skilled in the art are capable of carrying out suitablepolymerization of homopolymers, copolymers, terpolymers, etc., usingliquid, slurry or gas phase reaction conditions, using the guidelinesprovided herein.

[0064] Ethylene polymers of the invention include ethylene homopolymers,and interpolymers of ethylene and linear or branched higheralpha-olefins containing 3 to about 20 carbon atoms, with densitiesranging from about 0.90 to about 0.95 and melt indices of about 0.1 to200. Suitable higher alpha-olefins include, for example, propylene,1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, and3,5,5-trimethyl 1-hexene. Cyclic olefins such as vinyl cyclohexane ornorbornene may also be polymerized with the ethylene. Aromatic compoundshaving vinyl unsaturation, such as styrene and substituted styrenes, mayalso be included as comonomers. Particularly preferred ethylene polymerscomprise ethylene and about 1 to about 40 percent by weight of one ormore comonomers described above.

[0065] The invention will now be illustrated by examples exemplifyingparticularly preferred embodiments thereof Those skilled in the art willappreciate that these examples do not limit the invention but ratherserve to more fully describe particularly preferred embodiments.

GLOSSARY

[0066] In the the following examples, MI is the melt index (optionallytermed I₂), reported as grams per 10 minutes, determined in accordancewith ASTM D-1238, condition E, at 190° C.

[0067] FI is the flow index (optionally termed I₂₁), reported as gramsper 10 minutes, determined in accordance with ASTM D-1238 condition F,and was measured at ten times the weight used in the melt index test.

[0068] MFR is the melt flow ratio, which is the ratio of flow index tomelt index. It is related to the molecular weight distribution of thepolymer.

[0069] Productivity is given in Kg polymer/g procatalyst/hour/100 psiethylene.

[0070] The catalyst decay was determined by monitoring ethylene uptakein 1/min.

[0071] The polymer bulk density was determined by weighing 100 mlgraduated cylinder reactions carried out under a dry nitrogenatmosphere.

EXAMPLES Example 1

[0072] Halogenation by Contacting First with TiCl₄ and then with EADC:

[0073] Preparation of Precursor:

[0074] In this example, Mg(OEt)₂ (6.12 g, 53.5 mmol) and 2.8 g ofMg(OEt)(O₂COEt) (17.5 mmol) were initially slurried into 100 gm ofchlorobenzene (90 ml) in an 8 ounce bottle. Ti(OEt)₄ (3.76 g, 95%, 15.7mmol) was then added followed by the addition of 5.2 g of Ethanol. TiCl₄(2.0 g, 10.5 mmol) was added to the stirring slurry. The bottle wasplaced in a 100° C. oil bath and stirring continued at 440 rpm. By theend of 20 minutes, the reaction appeared to be a nearly water cleartranslucent slurry with a few granules of magnesium ethoxide remaining.After 70 minutes, the oil bath temperature was increased to 110° C., thebottle cap was removed and the contents subjected to a gentle stream ofnitrogen for an hour (to remove any excess Ethanol). The slightly cloudymixture was transferred to a glovebox and filtered warm. The solids werewashed once with chlorobenzene, twice with hexane then dried undermoving nitrogen. The yield was 6.0 g of white powder consisting ofgranules in the 15-20 μm range with a few spheres evident.

[0075] Preparation of Polymerization Procatalyst (Halogenation):

[0076] Approximately 2.11 g of the precursor obtained above was slurriedin 30 ml of hexane. To this slurry was added 4.4 ml of 4.54 MTiCl₄/toluene to obtain a yellow slurry. After stirring for 30 minutesat room temperature, the slurry was filtered. The solids were washedtwice with hexane and slurried again in 30 ml of hexane. Over about aminute, 18.5 ml of 25% of ethylaluminum dichloride in toluene wereadded. A dumpiness developed which disappeared upon addition of 25 ml oftoluene. After 20 minutes (with occasional stirring) the brown slurrywas filtered and the solids washed twice with hexane then dried undermoving nitrogen. Drying yielded approximately 1.38 g of yellow-brownpowder procatalyst (Ti=2.63%). A polymerization sample was made byslurrying 0.1005 g of this procatalyst in 20 ml of Kaydol brand mineraloil (0.60% solids).

[0077] Slurry Polymerization:

[0078] To a one liter stainless steel reactor containing 500 ml ofhexane and 15 ml of 1-hexene, were added 1024 standard cc of H₂ (33 psipartial pressure). Triethylaluminum (0.25 mmol of 1.56 M heptanesolution) was injected by syringe. The procatalyst prepared above andslurried in Kaydol oil (1.3 ml of 0.60% slurry) was injected from a 50ml bomb using ethylene pressure and about 20 ml of hexane. Afterpolymerizing for 30 minutes at 85°, while adding ethylene on demand tokeep the total pressure at 156 psi, the reaction was extinguished byinjecting 2 ml of isopropanol. Catalyst decay rate had been 47%/20minutes. The collected polymer was allowed to air dry overnight beforecharacterization. The slurry polymerization obtained about 203 g ofpolymer of 0.27 g/cc bulk density with melt index of 8.9 dg/min.Productivity was 50.9 Kg PE/g cat/hr/100 psi.

Example 2

[0079] Halogenation by Contacting First with EADC and then withAdditional EADC

[0080] Preparation of Precursor:

[0081] Carbonated magnesium ethoxide CMEO (0.6 g: 3.8 mmol), 7.55 gMg(OEt)₂ (66 mmol), 1.74 g of FeCl₃ (10.5 mmol) and 1.95 g MgCl₂.6EtOH(5.2 mmol) were mixed in an 8 ounce bottle to which was then added, 100gm of chlorobenzene (90 ml). The mixture was stirred for a minute, andthen 4.11 g of Ti(OEt)₄ (95%, 17.1 mmol) was added. The bottle wasplaced in a 100° oil bath and stirred at 440 rpm. After 27 minutes (96°oil) had elapsed, few of the granules had dissolved and there was someprecipitate evident in the brown liquid. After 3 hr, 47 min (97° oil),there were still granules present in a very thick slurry. By 5 hr, 41min, the slurry was so thick that the stir speed was increased to 550rpm, and at which time, a gentle nitrogen flow was started. At 6 hr, 39min, the stir speed was increased to 660 rpm and 40 ml of heptane wasadded over a period of 15 minutes. The heat was then turned off and theslurry allowed to stir overnight. The mixture was filtered in theglovebox. The solids were washed once with chlorobenzene then twice withhexane and sucked dry to yield 11.8 g of beige powder.

[0082] Preparation of Polymerization Procatalyst (Halogenation):

[0083] The solid precursor obtained above (2.12 g) was slurred in 15 mlof hexane, and 11 ml of 25% EADC/toluene was added to the slurry over aperiod of 3 minutes. The initially tan slurry turned to greyish brown.After stirring for 20 minutes the slurry was filtered. The solids werewashed twice with hexane and dried under moving nitrogen to give 2.15 gof grey powder. That powder was slurried in 15 ml of hexane, and then 11ml of 25% EADC/toluene was added over 2 minutes. The initially greyslurry turned brown. After 20 minutes stirring the mixture was filtered.The solids were washed four times with hexane and then dried undermoving nitrogen to give 1.57 g of tan powder. Analysis: 3.50% Ti, 3.09%Fe, 12.7% Mg, 4.64% Al. A polymerization sample was made by slurrying0.100 g of catalyst in 20 ml of Kaydol oil (0.60% solids).

[0084] Slurry Polymerizations:

[0085] A. To a one liter SS reactor containing 500 ml of hexane and 15ml of 1-hexene, were added 341 SCC of H₂ (13 psi partial pressure).Triethylaluminum (0.25 mmol of 1.56 M heptane solution) was injected bysyringe. The polymerization procatalyst prepared above (0.4 ml of 0.60%slurry) was injected from a 50 ml bomb using ethylene pressure and about20 ml of hexane. After polymerizing for 30 minutes at 85°, while addingethylene on demand to keep the total pressure at 160 psi, the reactionwas extinguished by injecting 2 ml of isopropanol. Catalyst decay ratehad been 67%/20 minutes. The collected polymer was allowed to air dryovernight before characterization. Obtained were 181 g of polymer of0.25 g/cc bulk density with melt index (I₂) of 0.204 dg/min and flowindex (I₂₁) of 6.88 dg/min (MFR=34). The polymer density was determinedto be 0.9459 g/cc. Size exclusion chromatography showed Mw/Mn=7.8.

[0086] B. Polymerization with diene comonomer: The polymerization inpart A was repeated except that the amount of catalyst slurry wasincreased to 0.7 ml and 5.0 ml of 5-vinyl-2-norbornene was added to thereactor. Obtained were 181 g of polymer of 0.22 g/cc bulk density withI₅ of 0.165 dg/min and flow index (I₂₁) of 6.88 dg/min (I₂₁/I₅=24,corresponding to an MFR>100). Size exclusion chromatography showedMw/Mn=10.9.

Example 3

[0087] Halogenation by Contacting First with DEAC and then with EADC

[0088] Preparation of Precursor:

[0089] Mg(OEt)₂ (8.6 g, 75 mmol) was slurried into 100 gm ofdecahydronaphthalene (112 ml), in an 8 ounce bottle, along with 0.27 gtriethyl borate (1.87 mmol). After stirring for about one minute, 4.11 gof Ti(OEt)₄ (95%, 17.1 mmol) and 1.97 g of TiCl₄ (10.4 mmol) were added.The bottle was placed in a 100-110° C. oil bath and stirred for 30minutes before adding a mixture of 4.0 ml of Ethanol (3.14 g, 68.2 mmol)and 2.0 ml of Butanol (1.61 g, 21.3 mmol). The solids clumped togetherinitially but then quickly dispersed as the granules began to dissolveto produce a homogeneous slurry. The slurry was then stirred for anotherhour at 540 rpm as all of the granular material appeared to havedissolved and the slurry had the appearance of a cloudy solution. Thecap was removed and a gentle nitrogen flow was maintained for an hour(until 6-8% of the solvent had evaporated). The slurry was filtered warmthen the solids were washed twice with hexane and dried under movingnitrogen to yield 8.05 g of white powder consisting of spheroidal,uniform sized particles.

[0090] Preparation of Polymerization Procatalyst (Halogenation):

[0091] About 2.25 g of the above-prepared magnesium andtitanium-containing procatalyst precursor was slurried into 20 ml ofhexane. To this were added 9 ml of a 25% solution of diethylaluminumchloride (DEAC) in toluene over 3 minutes as the slurry turned to grey.After stirring for 30 minutes the slurry was filtered. The solids werewashed twice with hexane and dried under moving nitrogen to produce apowder. That powder then was slurried in 20 ml of hexane, and then 9 mlof a 25% solution of ethylaluminum dichloride (EADC) in toluene wasadded over 2 minutes. The slurry turned brown. After 10 minutes withoccasional stirring the mixture was filtered. The solids were washedtwice with hexane, and then dried under moving nitrogen to produce 1.90g of brown powder procatalyst. A polymerization sample was made byslurrying 0.1076 g of this procatalyst in 20 ml of Kaydol oil (0.62%solids).

[0092] Slurry Polymerization:

[0093] To a one liter stainless steel reactor, containing 500 ml ofhexane and 15 ml of 1-hexene, were added 676 standard cc of H₂ (21 psipartial pressure). Triethylaluminum (0.25 mmol of 1.56 M heptanesolution) was injected by syringe. The above-prepared procatalyst (1.8ml of 0.62% slurry of procatalyst in Kaydol oil) was injected from a 50ml bomb using ethylene pressure and about 20 ml of hexane. Afterpolymerizing for 30 minutes at 85° C., while adding ethylene on demandto keep the total pressure at 156 psi, the reaction was extinguished byinjecting 2 ml of isopropanol. The catalyst decay rate had been 41%/20minutes. The collected polymer was allowed to air dry overnight beforecharacterization. The polymerization produced about 203 g of polymer of0.25 g/cc bulk density with melt index (I₂) of 1.69 dg/min and flowindex (I₂₁) of 62.4 dg/min (MFR=37).

[0094] Example 4

[0095] Halogenation by Contacting First with Br₂ and then with EADC:

[0096] Preparation of Precursor:

[0097] Approximately 8.15 g Mg(OEt)₂ (71.2 mmol) and 0.6 g magnesiumethyl carbonate (3.8 mmol) were mixed together with 100 gm ofchlorobenzene (90 ml), in an 8 ounce bottle, and then 4.11 g of Ti(OEt)₄(95%, 17.1 mmol) were added. After stirring the suspension for a minute,1.97 g of TiCl₄ (10.4 mmol) was added. The 8 ounce bottle was then wasplaced in a 100° C. oil bath and a mixture of 4.0 ml of Ethanol (3.14 g,68 mmol) and 1.5 ml of Butanol (1.21 g, 16 mmol) was quickly added. Themixture was stirred for 90 minutes at 440 rpm where it was observed thatall of the magnesium ethoxide appeared to have dissolved. The cap wasremoved from the bottle and the mixture stirred for ˜90 minutes under agentle nitrogen stream to remove Ethanol, (the volume decreased by about7%). The resulting slurry was transferred to a glovebox and filteredwarm. The solids were washed once with chlorobenzene, and then twicewith hexane and sucked dry to yield about 10.15 gm of white, uniformopaque spheroids clustered about 35 μm diameter.

[0098] Preparation of Polymerization Procatalyst (Halogenation):

[0099] Approximately 2.022 g of the precursor prepared above wasslurried in 25 ml of hexane, to which was then added a solution of 0.61g bromine in 10 ml hexane to obtain a dark red slurry which turnedcolorless after stirring for a few minutes. Toluene (15 ml) was added tothe slurry to break up some sticky clumps which had formed. Afterstirring for 25 minutes at room temperature, the slurry was filtered.The solids were washed twice with hexane and slurried again in 20 ml ofhexane. Over about a minute, 19 ml of 25% EADC/toluene were added. After15 minutes (with occasional stirring) the slurry had turned dark brown.The mixture was filtered and the solids washed twice with hexane thendried under moving nitrogen. Yielded 1.442 g of chocolate brown powder.A polymerization sample was made by slurrying 0.111 g of catalyst in 20ml of Kaydol oil (0.60% solids).

[0100] Polymerization:

[0101] To a one liter SS reactor, containing 500 ml of hexane and 15 mlof 1-hexene, were added 664 SCC of H₂ (25.6 psi partial pressure).Triethylaluminum (0.25 mmol of 1.56 M heptane solution) was injected bysyringe. The polymerization procatalyst prepared above (1.2 ml of 0.60%slurry) was injected from a 50 ml bomb using ethylene pressure and about20 ml of hexane. After polymerizing for 30 minutes at 85° C., whileadding ethylene on demand to keep the total pressure at 157 psi, thereaction was extinguished by injecting 2 ml of isopropanol. Catalystdecay rate had been 0.0%/20 minutes. The collected polymer was allowedto air dry overnight before characterization. Obtained were 96.5 g ofpolymer of 0.26 g/cc bulk density with melt index of 2.99 dg/min andflow index of 111.7 dg/min (MFR=37).

Example 5

[0102] Halogenation by Contacting First with TiCl₄ and then with DEAC,and then with TiCl₄

[0103] Preparation of Precursor:

[0104] The remaining examples utilize a magnesium/titanium containingalkoxide precursor as the starting precursor material. This material wasprepared by repeating illustrative embodiment II of U.S. Pat. No.5,124,298 on a scale sufficient to obtain 300 pounds of granularmaterial. Analysis (average of two runs): 12.3% Mg, 7.55% Ti, 60.3%Oet⁻, 0.93% o-cresol (Cl=11.5% by charge balance).

[0105] Preparation of Polymerization Procatalyst (Halogenation):

[0106] The precursor prepared above (5.00 g, 7.7 mmol Ti) was stirredwith a solution of TiCl₄ (16.9 g, 89 mmol) in 152 g of chlorobenzene.After 30 minutes, the mixture was filtered and the solids washed withchlorobenzene. The solids were then stirred with a solution of 42.97 gof 25% DEAC/toluene (89 mmol) in 77.54 g of toluene. After 30 minutesthe mixture was filtered and the solids washed first with toluene thenwith chlorobenzene. That dark brown precipitate then was stirred in asolution of 16.9 g TiCl₄ (89 mmol) in 152.1 g of chlorobenzene. After 30minutes, the mixture was filtered and the solids washed twice withisooctane then dried under moving nitrogen. The yield was 7.68 g of darkbrown powder. Analysis: 15.17% Ti, 7.59% Mg, 3.1% Al, 63.45% Cl. Apolymerization sample was made by slurrying 1.00 g of catalyst in 20 mlof Kaydol oil (5.3% solids).

[0107] Polymerization:

[0108] Ethylene gas was started flowing, at a rate of 1090 scc perminute, into a one gallon SS reactor, containing 1375 g of liquidpropylene and 45 mmol of H₂ (25.6 psi partial pressure). After 10minutes, the catalyst components consisting of Triethylaluminum (1.05mmol of 1.56 M heptane solution), dicyclopentyldimethoxy silane (0.18mmol) and the polymerization procatalyst prepared above (0.30 ml of 5.3%slurry) was injected via high pressure syringe utilizing about 20 ml ofisooctane. After polymerizing for 60 minutes at 45° C., with continuousethylene flow, the reaction was terminated by venting all monomers toatmospheric pressure. The collected polymer was allowed to air dryovernight before characterization. Obtained were 255 g of polymercomposed of 1-2 mm diameter balls. NMR analysis determined the polymerto be composed of 40% wt ethylene units and 60% wt propylene units.

Example 6

[0109] Halogenation by Contacting First with hot SiCl₄/TiCl₄ and thenwith EADC

[0110] Preparation of Polymerization Procatalyst (Halogenation):

[0111] To a 10 gal stainless steel reaction/filter vessel were charged1490 g of the precursor prepared in Example 5 above along with 6.0 kg ofhexane. Then a solution composed of 2235 g SiCl₄ and 1117 g TiCl₄ in 6kg of toluene was charged at such a rate as to keep the reactiontemperature between 25 and 30° (15-20 minutes). The slurry was heated to60° C. and stirred for 30 minutes and then filtered through an internalfilter plate. The solids were washed by reslurrying in a 50/50 mixtureof hexane and toluene then isolated by filtration. In a like manner, thesolids were then washed twice with hexane and dried under movingnitrogen.

[0112] The solids were reslurried into 5 kg of isopentane, and then asolution of 1531 g of EADC in 4.16 kg of toluene plus 2.89 kg of hexanewas added at such a rate as to keep the temperature between 25 and 30°(15-20 minutes). After stirring for 30 minutes at 25°, the slurry wasfiltered. The solids were washed once with 50/50 hexane/toluene thentwice with hexane and dried overnight under moving nitrogen. Yield 767grams of light brown powder. Analysis: 13.0% Mg, 1.96% Ti, 5.53% Al,61.7% Cl.

[0113] Polymerization:

[0114] To a one liter SS reactor, containing 500 ml of hexane and 15 mlof 1-hexene, were added 334 SCC of H₂ (15.5 psi partial pressure).Triethylaluminum (0.312 mmol of 1.56 M heptane solution) was injected bysyringe. The polymerization procatalyst prepared above (1.0 ml of 0.60%slurry) was injected from a 50 ml bomb using ethylene pressure and about20 ml of hexane. After polymerizing for 30 minutes at 85° C., whileadding ethylene on demand to keep the total pressure at 156 psi, thereaction was extinguished by injecting 2 ml of isopropanol. Catalystdecay rate had been 11.5%/20 minutes. The collected polymer was allowedto air dry overnight before characterization. Obtained were 142.8 g ofpolymer of 0.285 g/cc bulk density with melt index of 0.246 dg/min andflow index of 9.65 dg/min (MFR =39).

Example 7

[0115] Halogenation by Contacting First with SiCl₄/TiCl₄ Followed byEADC/BCl₃:

[0116] Preparation of Polymerization Procatalyst (Halogenation):

[0117] To a 10 gal stainless steel reaction/filter vessel were charged1892 g of the precursor prepared in accordance with Example 5 along with3.5 kg of hexane. Then a solution composed of 3.9 kg SiCl₄ and 713 gTiCl₄ in 6.6 kg of toluene was charged at such a rate as to keep thereaction temperature between 25 and 30° C. (15-20 minutes). The slurrywas stirred for 30 minutes and then filtered through an internal filterplate. The solids were washed by reslurrying in 15 kg of a 50/50 mixtureof hexane and toluene then isolated by filtration. In a like manner, thesolids were then washed twice with hexane and dried under movingnitrogen. Yield 2472 g of yellow powder. Analysis: 10.7% Mg, 9.82% Ti,36.2% Cl.

[0118] The 10 gal stainless steel reaction/filter vessel was rechargedwith 1302 g of the yellow powder along with 5 kg of hexane. Then, 7291 gof 25% EADC/toluene was added at such a rate as to keep the temperaturebetween 25 and 30° C. (15 minutes). Then 1175 g of 1M BCl₃/heptane wasadded all at once. After stirring for 30 minutes at 25° C., the slurrywas filtered. The solids were washed once with 50/50 hexane/toluene thentwice with hexane and dried overnight under moving nitrogen. Yield 1068grams of dark brown powder. Analysis: 10.7% Mg, 9.62% Ti, 2.38% Al,56.7% Cl. A polymerization sample was prepared by slurrying 0.100 g ofpowder in 20 ml of Kaydol mineral oil.

[0119] Polymerization:

[0120] To a one liter SS reactor, containing 500 ml of hexane and 15 mlof 1-hexene, were added 340 scc of H₂ (12.8 psi partial pressure).Triethylaluminum (0.312 mmol of 1.56 M heptane solution) was injected bysyringe. The polymerization procatalyst prepared above (1.0 ml of 0.60%slurry) was injected from a 50 ml bomb using ethylene pressure and about20 ml of hexane. After polymerizing for 30 minutes at 85° C., whileadding ethylene on demand to keep the total pressure at 155 psi, thereaction was extinguished by injecting 2 ml of isopropanol. Catalystdecay rate had been 6.3%/20 minutes. The collected polymer was allowedto air dry overnight before characterization. Obtained were 149.6 g ofpolymer of 0.30 g/cc bulk density with melt index of 0.196 dg/min andflow index of 8.96 dg/min (MFR=46).

[0121] As can be seen from the above examples, magnesium and transitionmetal-containing precursors can be halogenated by a variety of methodsto produce highly active polymerization procatalysts. In addition,varying the particular halogenation can produce procatalystsspecifically tailored to produce: (a) catalyst having varied decayrates; and (b) polymer having tailored molecular weight distributions.Using the guidelines provided herein, those skilled in the art arecapable of tailoring polymerization procatalysts to provide a variety ofcatalyst decay rates and polymers having a variety of molecular weightdistributions.

[0122] The inventive examples also provide polymerization procatalyststhat retain the excellent morphology of the precursor to therebygenerate polymer having fewer fines, as well as a higher bulk densityand a lower xylene solubles content. In addition, the halogenationprocesses of the present invention were effective in preparingpolymerization procatalysts that polymerize ethylene and propylene inhigh yield.

[0123] While the invention has been described in detail with referenceto particularly preferred embodiments, those skilled in the artappreciate that various modifications can be made without departing fromthe spirit and scope thereof. All documents referred to herein areincorporated by reference herein in their entirety.

What is claimed is:
 1. A method of making a solid composition useful as an olefin polymerization procatalyst without addition of an aromatic ester internal electron donor, said process comprising: preparing a solid composition comprising magnesium, titanium, halide, alkoxide and/or phenoxide moieties; chlorinating the solid composition by contacting the solid composition in the substantial absence of an aromatic ester internal electron donor one or more times with a chlorinating agent selected from the group consisting of alkylaluminum halides, TiX₄, SiX₄, BX₃, Br₂, and mixtures thereof, wherein X is halide, with the proviso that, if a single chlorinating agent is employed, the chlorinating is repeated one or more times; and recovering the solid composition.
 2. The method as claimed in claim 1 , wherein the solid composition corresponds to the formula: Mg₃Ti(OR)₈X₂, wherein, R is C₁₋₄ alkyl and X is halide or phenoxide.
 3. The method as claimed in claim 1 , wherein two chlorinating steps are employed.
 4. The method as claimed in claim 3 , wherein after the first chlorinating step the solid composition is recovered, rinsed with an alkane, and contacted with a different chlorinating agent in the second chlorinating step.
 5. The method as claimed in claim 4 , wherein one chlorinating agent is TiCl₄ and the other chlorinating agent is an alkylaluminum halide.
 6. A solid composition useful as an olefin polymerization procatalyst prepared in accordance with any one of the methods of claims 1-5.
 7. A method of polymerizing an olefin comprising contacting at least one olefin in the presence of the procatalyst, an organoaluminum cocatalyst compound, and optionally, a selectivity control agent, wherein the procatalyst composition is a solid composition according to claim 6 .
 8. The method as claimed in claim 7 , wherein the olefin is selected from the group consisting of ethylene, propylene, butylene and mixtures thereof. 